Student Paper: Challenges and Environmental Issues in the Development and Use of Lead-Free Solders

Student Paper: Challenges and Environmental Issues in the Development and Use of Lead-Free Solders
Amanda L. Schmidt; California Polytechnic State University

In 2003, the European Union (EU) passed directives Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (RoHS) and Waste Electrical and Electronic Equipment (WEEE). Lead, which is used in various processes in the semiconductor and electronics industry, including soldering is included in the RoHS Directive. Electronic waste is becoming more prevalent in landfills and lead contaminated leachate is reaching groundwater. Lead can cause learning deficiencies in children and kidney damage in adults. Industries are developing lead-free solders that have characteristics similar to leaded solders in performance and reliability; the most popular alternative alloys being SnAgCu or SnAgBi. This paper examined what environmental and health effects are associated with these new alloys. A study conducted by KTEC Electronics examined seven alloys of lead-free solders and exposed them to landfill conditions and found that silver and copper leaching occurred. Additionally, estimates from the United States Geologic Survey provide information on whether there are enough world reserves to sustain the new demand. Overall, this study provided the industry with criteria to weigh the various lead-free solder alloys to make the best environmentally sustainable choice.